Field of the Invention
The present invention relates to a treatment tool for an endoscope used together with an endoscope.
Description of Related Art
In the related art, as general methods of treating gastrointestinal tract lesions, endoscopic mucosal resection (EMR) in which lesion parts are resected using an endoscope is performed. In particular, endoscopic submucosal dissection (hereinafter referred to as “ESD”) is a method in which mucosae in the vicinity of lesion parts are cut and then submucosae are dissected to resect the lesion parts, which is known as reliable endoscopic therapy through which lesion parts could be resected entirely.
When such ESD is performed, a normal saline or the like is injected into normal mucosae in the vicinity of lesion parts using a needle and the lesion parts are lifted. In this state, a high frequency treatment tool such as a high frequency knife or a snare is used to resect a boundary between lesion parts and normal mucosae (for example, refer to Japanese Unexamined Patent Application, First Publication No. 2004-261372). In this case, in order to sufficiently lift the lesion parts up to a position so that a resection part of a boundary between lesion parts and normal tissues is sufficiently ensured, or in order to capture the resection part when the lesion parts have a flat shape, a transparent cap mounted on a distal end of the endoscope is inserted below mucosae to lift the mucosae, and the high frequency treatment tool proceeds with incision of submucosae.
However, since a distal end diameter of the transparent cap is greater than a distal end diameter of the endoscope, it is difficult to insert the endoscope into a fine incision wound and open the incision wound. In addition, even if a distal end cap is inserted into the incision wound, mucosae may slide off the distal end cap when the endoscope is operated to perform incision or dissection.
In order to prevent such problems, a treatment tool for an endoscope including a treatment part capable of capturing biological tissues such as mucosae is proposed (for example, refer to Japanese Patent No. 4980777 and Japanese Patent No. 4847354). According to the treatment tool for an endoscope, when a distal end cap is inserted below mucosae in order to cut submucosae, the treatment part can lift mucosae up, and submucosae can be viewed by the endoscope in a front view.
Moreover, a treatment tool for an endoscope in which a sheath to which a treatment part is connected is advanced or retracted in a central axis direction and the sheath is raised to separate a distal end of the treatment part from a distal end cap is disclosed (for example, refer to FIGS. 9 and 10 of Japanese Unexamined Patent Application, First Publication No. 2012-24597). All of these tools ensure a field of view of a portion to be cut by lifting mucosae up and pulling them toward the endoscope using the treatment part.